WO2018122365A1 - Measuring element, measuring system, and method of providing a measuring element for measuring forces - Google Patents

Measuring element, measuring system, and method of providing a measuring element for measuring forces Download PDF

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Publication number
WO2018122365A1
WO2018122365A1 PCT/EP2017/084791 EP2017084791W WO2018122365A1 WO 2018122365 A1 WO2018122365 A1 WO 2018122365A1 EP 2017084791 W EP2017084791 W EP 2017084791W WO 2018122365 A1 WO2018122365 A1 WO 2018122365A1
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WO
WIPO (PCT)
Prior art keywords
measuring
arm
measuring element
element according
measuring arm
Prior art date
Application number
PCT/EP2017/084791
Other languages
English (en)
French (fr)
Inventor
Martin Bleicher
Christoph Goeppel
Felix Greiner
Daniel LEIMINGER
Stefan Raab
Original Assignee
Te Connectivity Germany Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Te Connectivity Germany Gmbh filed Critical Te Connectivity Germany Gmbh
Priority to CN201780081500.4A priority Critical patent/CN110121636B/zh
Priority to JP2019535355A priority patent/JP2020514715A/ja
Priority to EP17822343.4A priority patent/EP3563131A1/en
Publication of WO2018122365A1 publication Critical patent/WO2018122365A1/en
Priority to US16/456,012 priority patent/US11346733B2/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/0057—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes measuring forces due to spring-shaped elements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/04—Measuring force or stress, in general by measuring elastic deformation of gauges, e.g. of springs

Definitions

  • the present invention generally relates to the field of measuring technology in which in particular forces with relatively small values of, for example, some centinewtons up to some hundreds of Newtons are to be measured, as is required for example for the measurement of spring forces of contacts in plug connections.
  • the contact force applied thereby should be both sufficiently large in order to produce, at the envisaged position, a relatively planar contact between the two contact surfaces and thereby to remove possible impurities, deposits and the like, so that a contact with as low a resistance as possible is brought into being.
  • the contact force applied thereby should however not be too large, because in that case relatively large forces are required during the deflection of the component exerting the contact force and in particular excessive wear on the contact surfaces can also occur in the event of repeated plugging-together and decoupling of the corresponding components.
  • a minimal contact force must be upheld in order to repeatedly provide the desired electrical and mechanical connection during the entire duration of the contact.
  • measuring elements or measuring transformers are employed which for example take over the role of a contact element, for instance a plug, and which are connected to the complementary plug device which is to be examined.
  • a measuring arm is used which, at given positions which come into contact with the complementary component, is equipped with a measuring cell which can output a corresponding signal when loaded with a force.
  • the measuring cell which is provided for example in the form of a piezoresisitive material or the like, is located precisely at the point at which a contact with the surface of the complementary component is produced, meaning that a more or less direct registering of the resulting normal force is possible.
  • a relatively exact correspondence between the registered force and the forces actually occurring between a plug connection arises only if the entire structure of the measuring arm, including the measuring cell, is modelled as identically as possible on the geometry of the corresponding point in the component to be examined, because otherwise in the event of diverging geometry there arises a force which does not correspond to the actual conditions.
  • the direct contact between the measuring cell and the complementary region of the plug connection can lead to increased wear on the measuring cell, particularly if frequent measurements are carried out in order to economically exploit the measuring system efficiently.
  • a suitable coating is typically applied in order to increase the mechanical strength of the measuring cell.
  • an appropriate mechanical or more robust coating the response sensitivity of the measuring cell and thus the exactness and the resolution of the measurement results obtained is possibly reduced.
  • an "indirect" registering of the forces is carried out by a suitably formed pair of measuring arms being provided which, in terms of their geometry and material characteristics, can be modelled to a large extent on the actual conditions, which however enable a relative deflection relative to one another which is then detected at a suitable point of the measuring system.
  • document DE 25 56 836 describes a measuring element and a measuring head for measuring small forces, in particular contact spring forces, wherein the measuring element consists of a one-piece plate which has two legs formed by slots that are connected to one another via a short web.
  • the connecting web is for instance of the size of the slot and the strain gauge has an extent which is substantially greater than the web connecting the two legs.
  • the conventional systems described by way of example with reference to the two printed documents do permit an efficient ascertainment of spring forces in a correspondingly limited measurement range, but with the response sensitivity and the resolution and measurement exactness possibly being relatively low in the "directly" measuring system due to the structure of the measuring cell and, in the event of frequently repeated measurement, there occurring, due to the unavoidable wear, a change in the overall geometry of the measuring cell which may not be noticed for a long time and which in turn has an influence on the forces ascertained, is generated.
  • an aim of the present invention is to specify means with which forces, for example of spring forces of plug connections, can be ascertained with increased response sensitivity and/or improved repeatability and/or increased exactness, with as realistic a modelling of the plug connection systems as possible being meant to be possible.
  • the aforementioned aim is achieved according to one aspect of the present invention through a measuring element for detecting forces.
  • the measuring element according to the invention comprises a first measuring arm which extends in a longitudinal direction of the measuring element and a second measuring arm which extends in a longitudinal direction, wherein the first and the second measuring arms can be deflected relative to one another in a direction perpendicular to the longitudinal direction.
  • the measuring element further comprises a deformation section that connects the first measuring arm and the second measuring arm to one another in an elastically deformable manner and which has a first side facing the first and second measuring arms and a second side facing away from the first and second measuring arms.
  • the measuring element according to the invention further comprises at least one transformer unit which is arranged on the first side and/or the second side of the deformation section, and which responds to deformation and which is situated fully within the deformation section.
  • the measuring element according to the invention is therefore distinguished by there being provided two measuring arms that are deflectable relative to one another and that can be produced and arranged in any suitable form, in order to thus realistically model a corresponding application purpose.
  • the two measuring arms are connected to one another by a deformation section in an elastically deformable manner, so that the relative deflection can be detected via the deformation section.
  • at least one transformer unit is fully arranged in the measuring element according to the invention, on the side of the deformation section facing the measuring arms or the facing-away side of the deformation section.
  • the measuring element according to the invention corresponds to the "indirect” measuring concept and thus enables a high degree of robustness and adaptability of the corresponding measuring arms to the envisaged application purpose, while on the other hand the deformation caused by the relative deflection of the first and of the second measuring arms can be efficiently captured by suitable positioned transformer units.
  • the deformation section is designed here such that the at least one transformer unit is fully accommodated on the deformation section, as a result of which it is on the one hand defined that the deformation section itself is of a sufficient size to receive the first transformer element and is furthermore suitably formed to enable the positioning of the transformer unit both on the side facing the measuring arms and/or on the facing-away side.
  • the expected deformation is "distributed" on a larger region, as a result of which there emerges an improved resolution.
  • the one or more transformer units cover a larger surface of the deformation section and therefore output one or more signals which enable an evaluation of the registered force region with greater exactness and/or higher resolution, i.e. with greater linearity, lower temperature dependency and lower dependency on non-optimal plugging, for instance components which are plugged in askew in the event of manual handling.
  • two or more transformer units are provided which are arranged on the first side and/or the second side of the deformation section and which respond to deformation.
  • two or more transformer units are therefore provided on the facing-away side or the facing side or on both sides, so that there is overall likewise a suitable geometry of the deformation section here such that the arrangement of these two or more transformer units fully within the deformation section is made possible.
  • the selection of the number and the positions of the corresponding transformer units can therefore be carried out with regard to obtaining corresponding signals in an optimised manner.
  • a spatially resolved ascertainment of the deformation components can take place in the deformation section such that the evaluation can gain exactness and/or the response sensitivity can be increased through the presence of two or more independent pieces of information.
  • the deformation section which can fully receive at least one transformer unit and in further preferred embodiments two or more transformer units, improved response behaviour and greater exactness, i.e. with greater linearity, lower temperature dependency and lower dependency on non-optimal plugging, for instance components which are plugged in askew in the event of manual handling, can be achieved when evaluating the deformation of the deformation section.
  • a geometric design of the deformation section is modelled on a geometric design ascertained by simulating the deformation behaviour for a given range of forces, which must be measured through relative deflection of the first and second measuring arms.
  • the geometric design of the deformation section is ascertained, on the basis of the material characteristics of the deformation sections and with regard to the forces which are to be expected and which are to be measured, through simulation and this simulated geometric configuration is then modelled using the appropriate material, so that a high degree of "similarity" of the "behaviour” of the simulated geometric design and the actually produced geometric design is achieved.
  • the geometry of the deformation section which is significant for translating the force to be measured into a corresponding signal, can be efficiently adapted by modelling a simulated structure, which can be calculated with virtually any level of exactness desired, for the application which is of interest.
  • a desired degree of precision of the measurement results, which are to be expected, with regard to the previously ascertained measurement range can, however, be achieved by suitably selecting the geometric design.
  • good response behaviour is achieved on the basis of the appropriately arranged transformer units.
  • a position of the at least one transformer unit is in a region ascertained through simulation and/or in a region with the locally highest deformation.
  • the geometric designing of the deformation sections is carried out such that the one or more transformer units can be fully provided on the deformation section, wherein additionally corresponding positions are selected for the transformer units, which, in combination, output an optimised signal and/or sustain a locally highest degree of deformation in the event of relative deflection of the two measuring arms.
  • These regions with the locally highest deformation in the deformation section can be ascertained, for example, experimentally for a given geometric design or on the basis of simulation.
  • the regions "with locally highest deformation” must be understood such that if a region with the locally highest deformation is provided for a position of a single transformer unit, in the region of the largest value of deformation, be it contraction or expansion, is achieved for all positions within that face of the deformation section which is covered by the transformer unit. It is similarly the case that if two or more regions are provided with locally highest deformation, these regions each contain a maximum local value of the deformation in the face covered by the respective transformer unit and all other deformation values within the covered face of the corresponding two or more regions are smaller than the local maximum values ascertained in the respective regions.
  • the measuring element has a first measurement range which is fixed in that when a force which is to be measured through relative deflection of the first and the second measuring arm and which is equal to or smaller than a first threshold exerts an effect, the first measuring arm and the second measuring arm remain spaced apart from one another.
  • a force which is to be measured exerts an effect within the given regions
  • an intermediate space is always preserved between the first measuring arm and the second measuring arm, so that a direct contact of the measuring arms is avoided.
  • even very small forces can be reliably registered with suitable resolution because the relative deflection does not lead to any direct contact and thus does not lead to any "falsification" of the small force which exerts an effect.
  • the measuring element has a second measurement range which is fixed in that when a force which is to be measured through relative deflection of the first and second measuring arms and which is greater than the first threshold exerts an effect, a front region of the first measuring arm is in contact with a front region of the second measuring arm.
  • the second measurement range therefore differs from the first measurement range at least in that the first measuring arm and the second measuring arm are in contact, which indicates a mechanical state which is detectable.
  • the measuring element has a third measurement range which is fixed in that when a force which is to be measured through relative deflection of the first and the second measuring arm and which is greater than the first threshold and equal to or greater than a second threshold which is above the first threshold exerts an effect, the front region of the first measuring arm is in contact with the front region of the second measuring arm and a size of an intermediate space formed by a rear region of the first measuring arm and a rear region of the second measuring arm is characteristic of the force which is to be measured.
  • the relatively large force to be measured produces a contact between the first and the second measuring arm, but when the force is further increased said contact differs little from the state of the contact caused by a smaller force, but with the size of the intermediate space of the rear regions being a measure for actual size.
  • the relative deflection of the first and of the second measuring arms, which is measured via the deformation section is still only relatively small, since for example substantially only a deformation of the first and of the second measuring arms takes place, an additional classification of the acting forces can nevertheless be carried out by further evaluating the size of the intermediate space.
  • three pieces of information are fundamentally available for the ultimate estimation of the force, i.e. the deformation of the deformation section, the knowledge that the front regions of the first and of the second measuring arm are in contact, and the adjusting size of the intermediate space.
  • a very wide range of forces can thus be covered compared to conventional systems by evaluating additional information which can be ascertained by different mechanical states of the first and of the second measuring arm.
  • a first detecting device which is formed to register the contact of the front region of the first measuring arm with the front region of the second measuring arm.
  • the detecting device can in this case be a pressure-sensitive system that is provided on the first measuring arm or the second measuring arm or on both and that outputs a pressure-dependent signal.
  • a piezoelectric material can be provided, which outputs a pressure-dependent electrical signal when pressure is loaded on.
  • the mechanical stress is relatively small here, because for example only a precisely defined mechanical contact takes place, perpendicular to the longitudinal direction of the measuring element, by the first measuring arm and the second measuring arm, while no direct contact to an object to be measured occurs, and in particular no displacement in the longitudinal direction of the detecting device.
  • Other pressure-sensitive sensors which are on a capacitive, acoustic, piezoresistive, resistive or optical basis or on the basis of high-frequency electromagnetic fields can also be used in order to output an appropriate signal.
  • the knowledge of the contact between the first measuring arm and the second measuring arm can be obtained for instance on the basis of an electrical resistance measurement, if, for example, the measuring arms connected to one another via the deformation section have a relatively high resistance, while, in the case of a "short circuit" brought about by contact, a significantly lower resistance arises.
  • the first measuring arm and/or the second measuring arm and/or the deformation section can, at least in sections, contain an insulating material, so that a very high resistance arises when the measuring arms are in the "open” state, whereas a significantly lower resistance can be measured in the "closed", i.e. contacted state.
  • a second detecting device which is formed to register the size of the intermediate space.
  • this second detecting device it is possible to register the size of the intermediate space, which is dependent on the force which is exerting an effect and thus to provide it as information for the evaluation of the force which is exerting an effect.
  • the second detecting device can thereby be designed for example on the basis of electrical measurement principles, for instance a capacity measurement, resistance measurement, acoustic impedance measurement, inductive coupling, electromagnetically high-frequency impedance measurement or optical measurement and the like, while in other variants corresponding devices which detect the deformation can be provided in the form of a resistive, piezoresisitive, optical, acoustic or electromagnetically high-frequency active strain gauges, and the like, in order to evaluate the size of the intermediate space which arises according to the force which is exerting an effect through a change in the form of the first and/or of the second measuring arm.
  • electrical measurement principles for instance a capacity measurement, resistance measurement, acoustic impedance measurement, inductive coupling, electromagnetically high-frequency impedance measurement or optical measurement and the like
  • corresponding devices which detect the deformation can be provided in the form of a resistive, piezoresisitive, optical, acoustic or electromagnetically high-frequency active strain gauges, and the like, in
  • a first surface of the first measuring arm is opposite a second surface of the second measuring arm, the first and the second surface are formed complementary to one another and have surface regions with a surface normal which forms an angle to the relative deflection.
  • those surfaces of the measuring arms which face one another are formed complementary to one another, so that for example, if the two surfaces are hypothetically laid one on top of the other, a certain form- fit would be created.
  • certain surface regions are oriented such that they are angled relative to the direction of the deflection, i.e. relative to the direction of the force which is exerting an effect and which leads to the relative deflection of the first and of the second measuring arm.
  • This geometric characteristic can for example be achieved by arched sections or conical sections in the respective surfaces with their associated complementary surface forms or also by two otherwise level smooth surfaces, which, however, are inclined to the direction of the deflection.
  • the two facing surfaces are level faces with normals which are parallel to the direction of the measuring forces.
  • the measuring element is structured such that a total thickness of the first and of the second measuring arm is designed within an interaction region such that, in a state without action of a force that is to be measured, it varies and/or is variable.
  • the measuring element according to this variant has at least different total thicknesses in the interaction region, i.e. in the region in which one or more forces to be measured exerts an effect on the first and/or the second measuring arm, so that different situations can be modelled with regard to an object which is to be measured.
  • regions with different lateral dimensions for example may be present, for instance in order to elict different contact forces along different positions in the longitudinal direction, so that such a situation can be modelled with a structure with a different total thickness in the interaction region.
  • regions with different lateral dimensions for example may be present, for instance in order to elict different contact forces along different positions in the longitudinal direction, so that such a situation can be modelled with a structure with a different total thickness in the interaction region.
  • the total thickness is variable so that for example for a given position at which a force to be measured exerts an effect, one or more different thicknesses and possibly also a corresponding profile can be adjusted in order to obtain a more detailed statement on the behaviour of respective connection components.
  • the interaction region has a varying total thickness which is caused by a varying thickness of the first and/or of the second measuring arm in the region of +/- 200 ⁇ .
  • an actuator element with adjustable elongation/contraction is provided in a first connection region, which is coupled with the first measuring arm, and/or a second connection region, which is coupled with the second measuring arm, and/or the deformation section.
  • a controllable change in the dimension can thus be controllably caused in a respective section of the corresponding component, as a result of which the mechanical behaviour, for example, of the measuring element can be adjusted as a whole.
  • the actuator element can be arranged such that a change in its expansion/contraction leads to a change in the spacing of the two measuring arms and thus a different total thickness is obtained.
  • the total thickness of the measuring arms can be altered from 0.001 to 2.0 mm.
  • the response behaviour of the measuring element can be controllably adjusted, for instance in order to model a certain range of different lateral dimensions of a real structural element.
  • the change in the configuration of the measuring element for example the total thickness of the first and second measuring arms, can be performed before a planned measuring and indeed before contact with the measurement object but also during contact with the measurement object.
  • Suitable actuator elements are for example piezo-electrical components with which it is possible to adjust an elongation/contraction by applying a suitable control voltage, an electromagnetic or electrodynamic rotation actuator with spindle gear or a manual spindle gear.
  • other mechanisms which provide a change of the dimensions in the suitable region can also be used.
  • the spring characteristic is adjusted depending on the client's tolerance range, or the change in thickness takes place depending on the product.
  • a measuring element therefore covers a large range of products. It is thus also possible to examine new products for which there is not yet any specific measuring element. thickness change not plugged in without force applied, i.e., static thickness change. Therefore a different measuring situation can be firmly and unchangeably adjusted. Foils are therefore suitable for application for this purpose in order to alter the thickness of one or both measuring arms, but also "statically" used actuator elements, in particular a manual spindle gear.
  • the one or more actuator elements serve as a sensor.
  • the concept of compensation can be used in some embodiments with the aid of the actuator element. In this case, the stroke performed by the actuator element and/or the work applied by the actuator element until a particular signal of the transformer unit is achieved is evaluated.
  • a positioning element is provided at the first and/or the second measuring arm for positioning a calibration mass or a calibration length element.
  • Corresponding measuring elements are frequently calibrated by exerting an effect with a gauged weight or according to a calibrated length, for example by the weight being added to the corresponding measuring arm and/or by a defined length deflection being caused and by the resulting deflection being ascertained.
  • the positioning element is a groove formed in the respective measuring arm or a corresponding notch, which can suitably surround and thus position a string or other line used to suspend the calibration mass.
  • a measuring element for measuring forces which has a first measuring arm which extends in a longitudinal direction of the measuring element and a second measuring arm which extends in a longitudinal direction, wherein the first and the second measuring arms can be deflected relative to one another in a direction perpendicular to the longitudinal direction.
  • the measuring element according to this aspect further comprises a deformation section which connects the first measuring arm and the second measuring arm to one another in an elastically deformable manner.
  • the first measuring element has a first measurement range which is fixed in that when a force which is to be measured through relative deflection of the first and the second measuring arm and which is equal to a threshold or smaller than the threshold exerts an effect, the first measuring arm and the second measuring arm remain spaced apart from one another. Furthermore, the measuring element has a second measurement range which is fixed in that when a force which is to be measured through relative deflection of the first and of the second measuring arm and which is greater than the first threshold exerts an effect, a front region of the first measuring arm is in contact with a front region of the second measuring arm.
  • an assessment of the force to be measured takes place on the basis of the deformation of the deformation section, wherein overall a broadened measurement range and/or a greater exactness can be achieved by at least the two measurement ranges being provided which differ from one another by contact and non-contact of the front regions of the measuring arms.
  • the measuring element is formed such that for a force up to a certain threshold force, when exerting an effect onto the measuring element, a mechanical contact between the first and second measuring arm is avoided, so that in this case a favourable response behaviour can be achieved for relatively small forces, for example in the range of a few tens of Newtons up to a few hundreds of Newtons, because substantially only the elastic spring force of the deformation section occurs as a counter force for the force to be measured.
  • a mechanical contact of the two measuring arms takes place so that the mechanical characteristics of the measuring arms themselves also play an increasingly important role as a counterforce for the force to be measured.
  • a third measurement range which is fixed in that when a force which is to be measured through relative deflection of the first and second measuring arms and which is greater than the first threshold and equal to or greater than a second threshold that is above the first threshold exerts an effect, the front region of the first measuring arm is in contact with the front region of the second measuring arm and a size of an intermediate space formed by a rear region of the first measuring arm and a rear region of the second measuring arm is characteristic of the force which is to be measured.
  • a first detecting device is provided for registering the contact of the measuring arms, where necessary in connection with a second detecting device which registers the size of the intermediate space.
  • suitable signals for instance electrical signals, can be obtained by the respective detecting devices, in order to evaluate the information obtained through the respective mechanical state of the measuring arms.
  • one or more transformer units that respond to deformation are provided on the deformation section.
  • the deformation section is designed geometrically such that at least one, preferably several, transformer units can be accommodated thereon, so that an efficient and precise ascertainment of the deformation of the deformation sections can take place.
  • a strain gauge is used, this may be arranged such that it is applied in the full length on the deformation section so that a high response property is achieved in connection with good resolution of the deformation which is to be registered.
  • one of the one or more transformer units is arranged on a side of the deformation section facing the measuring arms.
  • the deformation section is formed at least such that it is possible to arrange the transformer unit on the facing side, as a result of which a position is available which is not possible, for example, in the aforementioned conventional, indirect measuring arrangement.
  • one or more transformer units can also be arranged on the side facing away from the measuring arms, in order in turn to thus increase response properties and/or exactness and/or resolution.
  • a geometric design of the deformation section is preferably modelled on a geometric design ascertained by simulation, as has also already been explained in connection with the first aspect.
  • a substantial aspect of the measuring element can be fixed such that an adaptation to the intended application is possible with a high degree of exactness, with a large span of forces to be measured being able to be covered due to the implementation of at least two different measurement ranges.
  • a position of the transformer unit is fixed on a region with the locally highest deformation, which region is ascertained by experimentation and/or simulation.
  • appropriate measures are taken, which are also explained in connection with the first aspect.
  • those surfaces of the measuring arms which face one another are suitably formed, as also explained previously, and/or the total thickness of the first and second measuring arms varies or is adjustable, as has also been described previously.
  • the thickness can vary in the range of +/- 200 ⁇ and/or separate regions can be provided which each have a thickness which is uniform but which can be different from region to region and/or an actuator element can be provided at a suitable point in the measuring element, in order to adjust the mechanical characteristics, for example the total thickness, for instance in the range of 0.2 mm to 2.0 mm as desired.
  • suitable means can be provided in order to guarantee an exact position of the point of action of a calibration mass or of a calibration length element.
  • the aforementioned aim is achieved by a measuring element for registering forces, which has a first measuring arm, which extends in a longitudinal direction (L) of the measuring element, with a front region and a rear region.
  • a second measuring arm which extends in the longitudinal direction, is provided with a front region and a rear region, wherein the rear regions of the first and of the second measuring arm can be deflected relative to one another in a direction perpendicular to the longitudinal direction and the front regions are firmly connected to one another.
  • the measuring element further comprises a detecting device for registering a size of an intermediate space which is formed by the rear regions of the first and second measuring arms.
  • the detecting device comprises one or more transformer units which respond to deformation of the rear region of the first and/or of the second measuring arm.
  • the detecting device has, additionally or as the sole detecting means, the components which respond to deformation, for instance thin metal film strain gauges and/or a silicon strain gauge and/or a polymer strain gauge and/or a piezo-electrical device, etc. and/or an optical transformer unit and/or high-frequency electromagnetic transformer unit and/or an acoustic transformer unit, which enable high precision.
  • the detecting device comprises a device which registers the spacing between the rear region of the first measuring arm and the rear region of the second measuring arm, as a result of which, alternatively or in addition to the aforementioned transformer units, further measuring concepts, for instance capacitive and/or inductive space measuring, ultrasound measuring, optical space measuring, electromagnetic space measuring and the like, can be used. In this manner, response sensitivity and exactness can be further increased.
  • the first and the second measuring arm are elastically coupled with one another on a side facing away from the front regions.
  • the elastic coupling is carried out by a deformation section which is provided with one or more transformer units which register a deformation of the deformation section.
  • the transformer units can be part of the detecting device or can be provided in addition thereto.
  • the aforementioned problem is solved by a measuring system for detecting forces.
  • the measuring system comprises a measuring element, as described in one of the preceding embodiments or as explained in the following detailed description.
  • the measuring system has a calibration unit which can be coupled with the measuring element and which, in the coupled state, fixes a position at the first and/or the second measuring arm for loading with a calibration force or for applying a calibration length element.
  • the advantageous effects of the previously explained measuring element can be further strengthened by an extremely reliable calibration being made possible by the calibration unit.
  • the calibration unit is provided in the form of a receptacle which receives a part of the two measuring arms in a precise manner and thereby exposes a precisely fixed region of the first measuring arm and/or of the second measuring arm on which the desired calibration force can then act.
  • the receptacle can have the form of a cap or a cup that, through its geometry, enforces a precise position of the two measuring arms inside the cap or cup when the first and the second measuring arm are introduced.
  • the calibration force can be exerted for example by a weight belonging to the calibration unit, or a separate weight.
  • the one or more apertures in the calibration unit can serve as a guide for a pressure rod which itself serves as a calibration mass or which, in connection with an additional mass, functions as a calibration mass in order to thus exert the desired calibration force at the precisely fixed position.
  • the aforementioned problem is solved by a method of providing a measuring element, wherein the measuring element has the characteristics of one or more of the previously demonstrated embodiments.
  • the method comprises the selection of a material at least for the production of the deformation section of the measuring element and the fixing at least of a measurement range for forces to be measured through relative deflection of the first and of the second measuring arms. Furthermore, one or more materials and one or more modes of operation are selected for one or more transformer units which respond to deformation.
  • the method further comprises ascertaining a simulated geometric design of the deformation section by taking material characteristics of the selected material and of the fixed measurement range as the basis by carrying out a simulation calculation. Finally, the method comprises the production of the deformation section from the selected material by modelling the simulated geometric design.
  • a material for the deformation section and one or more transformer units are firstly selected and one or more possible geometries are ascertained with regard to a desired measurement range, i.e. with regard to the range of the size of the forces to be measured, wherein this advantageously takes place such that a high degree of exactness and/or good response properties and/or a high resolution arise for the selected measurement range.
  • a desired measurement range i.e. with regard to the range of the size of the forces to be measured
  • the simulation also takes place from the aspect of ascertaining one or more favourable positions for one or more transformer units which are to be arranged on the deformation section.
  • the term of the position of a transformer unit should be understood such that the size and form of the region and thus of the transformer unit are thus also defined.
  • the simulation calculation can be performed in one advantageous embodiment on the basis of the finite elements method. It is well-known that the finite elements method is particularly advantageous for performing a simulation with a computer, because the development of this method is always carried out in interaction with computer-aided tools and thus enables an efficient implementation on any desired suitable computer platform.
  • Fig. 1 a is a schematic side view of a measuring system according to one embodiment
  • Fig. 1 b to Fig. 1 d are schematic side views of a deformation section with different geometries and different positions and number of transformer units for deformation-dependent signal output
  • Fig. 2a is a schematic side view of a measuring system according to one further embodiment, in which different mechanical states are used to implement different measurement ranges,
  • Fig. 2b to Fig. 2d show three different mechanical states of the measuring element
  • Fig. 3a to Fig. 3e show schematic perspective views of cross-sections and thus of surfaces, which face one another, of the measuring arms according to various embodiments,
  • Fig. 4a shows a schematic side view of a measuring system having varying or variable total thickness of the measuring arms
  • Fig. 4b depicts an embodiment in which the thickness of one or both measuring arms is adjusted differently in different regions
  • Fig. 4c schematically shows an embodiment in which an extent/contraction of a part of the measuring element can be altered in a controllable manner
  • Fig. 5 shows a schematic side view of a part of the two measuring arms, wherein a section that is not sensitive to force is provided
  • Fig. 6 schematically shows a perspective view of a variant in which several pairs of measuring arms are provided in order to measure simultaneously several forces independently of one another
  • Fig. 7 schematically shows a side view of a part of the measuring element with adapted cross-sections
  • Fig. 8a shows a schematic side view of a measuring system from a further embodiment, wherein a separate calibration unit is provided
  • Fig. 8b shows a variant in which, alternatively or in addition to the calibration unit, a positioning element is provided for exactly fixing a calibration force
  • Fig. 8c schematically shows a side view of a part of the measuring system from Fig. 8a, wherein a part of the measuring arms is positioned in the calibration unit and is loaded with a measuring force with high local resolution. Additional embodiments of the present invention will now be described in greater detail with reference to the accompanying drawings.
  • Fig. 1 a shows a schematic side view of a measuring system 180 which is formed for measuring forces, in particular forces in the region of a few centinewtons up to some hundreds of Newtons, wherein in this case the component of a respective force, which is oriented perpendicular to a longitudinal direction L of the system 180 and which is situated in the plane of projection of Fig. 1 a, are registered.
  • forces in particular forces in the region of a few centinewtons up to some hundreds of Newtons
  • the component of a respective force which is oriented perpendicular to a longitudinal direction L of the system 180 and which is situated in the plane of projection of Fig. 1 a
  • forces can possibly act onto the system 180 at a certain angle, with that corresponding component of this force which is situated in the plane of projection of Fig. 1 a and oriented perpendicular to longitudinal direction L is measured.
  • a small angular deviation regarding the previously ascertained force direction can occur due to a slight deflection or deformation in the measuring system 180.
  • the system 180 comprises a calibration unit 190 which serves to exert a given known force at the system 180 at a precisely specified position, as is also explained in greater detail below.
  • the system 180 further comprises a measuring element 100 which is the component of the system 180 which is loaded with a force which is to be measured and provides a signal corresponding to this force.
  • the measuring element 100 comprises a first measuring arm 1 10 and a second measuring arm 120, which in the unstressed state form therebetween a spacing 101 which, depending on the application, can have a size from some tenths of a millimeter up to a millimeter or more.
  • the first measuring arm 1 10, which has a front region 1 10A and a rear region 1 10B, and the second measuring arm 120, which similarly has a front region 120A and a rear region 120B, are mechanically coupled to one another via a deformation section 130, so that a relative deflection of the measuring arms 1 10, 120 relative to one another, which leads to a change in the spacing 101 , causes an elastic deformation of the section 130, this deformation being transformed into a signal via suitable means.
  • suitable means for transforming the deformation into a signal are not shown in Fig. 1 a.
  • the measuring arms 1 10, 120 are connected by means of corresponding legs or transition regions 1 15, 125 to the deformation section 130.
  • the transition regions 1 15, 125 are typically configured such that they show a merely negligible deformation when they are loaded with a force which has the previously described orientation.
  • the geometric arrangement made up of the measuring arms 1 10, 120, the transition regions 1 15, 125 and the deformation section 130 is structured such that, when a relative deflection of the measuring arms 1 10, 120 takes place, a noticeable deformation occurs only in the deformation section 130 and, as described below, to a certain extent at the measuring arms 1 10, 120 too. It should be noted that, when the measuring arms 1 10, 120 are in the "unstressed” state, small forces can nevertheless exert an effect on the measuring arms 1 10, 120, but these cause substantially no noticeable deformation, in particular in section 130.
  • gravity can act downwards perpendicularly to the longitudinal direction L and this force leads to no measurable deformation, even if only a part of the measuring element 100 is rigidly connected to an additional body, for instance a housing (not shown).
  • the deformation section 130 has in particular a pronounced length in the direction perpendicular to longitudinal direction L, so that, depending on the material and geometry, the deformation section 130 can register a desired response sensitivity even in the case of small deflection of the measuring arms 1 10, 120.
  • one or more transformer units which are formed to transform a deformation of the section 130 into a signal are attached at given positions, for instance on a side 130A facing the measuring arms 1 10, 120 and/or on a side 130B facing away from the measuring arms 1 10, 120.
  • a "height" or material wall strength i.e.
  • the dimensions of the material in a direction perpendicular to the plane of projection from Fig. 1 a, in particular of the deformation section 130 also has a significant influence on the deformation characteristics of the section 130 and therefore is also taken into account when selecting the geometric design of the deformation section 130.
  • Fig. 1 b shows a schematic side view of the deformation section 130, the geometric design of which is adapted to the respective application such that a desired degree of response sensitivity, exactness and resolution is achieved for the deformation brought about by a deflection of the measuring arms.
  • the deformation section 130 substantially corresponds to a more or less rectangular section with relatively sharp edges 131 , i.e. with a corresponding transition to the connection regions 1 15, 125 (Fig. 1 a), so that a correspondingly exactly defined length 130L can be specified which corresponds to the spacing of the sharp edges 131 .
  • the length 130L can be in the region of 5 mm to 20 mm or greater.
  • the length 130L is in this case selected here such that at least one transformer unit can be fully arranged thereon.
  • the geometric design of the deformation section 130 is ascertained starting from the material characteristics, i.e. modulus of elasticity, wall thickness, and the like, on the basis of a simulation calculation, in which a fictive deformation section is constructed on the basis of a suitably selected number of finite elements and the mechanical behaviour in the event of bending forces occurring is ascertained.
  • the bending forces entering into the calculation can be ascertained in this case on the basis of the geometric design of the measuring element 100, for example if it is assumed that at a given length along the longitudinal direction L (Fig. 1 a) a certain range of forces acts onto the measuring arms and are ultimately transmitted via the transition regions onto the deformation section 130.
  • the geometric design of the deformation section 130 is here firstly ascertained by calculation depending on the other factors and in particular the material characteristics for a given wall thickness, such that a desired mode of operation of the measuring systems is guaranteed over a given range of forces exerting an effect.
  • corresponding regions with the locally highest deformation it is also possible for corresponding regions with the locally highest deformation to be ascertained in the event of given force acting onto the measuring arms and to be ascertained as suitable positions, i.e. location and expansiveness for corresponding measuring transformers.
  • the position i.e. the situation, for instance the situation of a mid point
  • the dimensions of a transformer unit 140 are determined in order to thus obtain a desired degree of resolution, exactness, response sensitivity, and the like.
  • the transformer unit 140 is provided fully at the central location within the extent 130L of the deformation section 130, because the greatest values of the deformation have been calculated there.
  • the transformer unit 140 is arranged fully within the deformation section 130, on its facing-away side 130B.
  • a further transformer unit 141 with suitable dimensions can be arranged on the facing side 130A, wherein here too the exact situation and dimensions of the transformer unit 141 are given by the simulation calculation.
  • Fig. 1 c shows a further variant in which the geometric design differs from the design in Fig. 1 b, for instance in terms of the length 130L and/or the representative width 130D which is, for instance, measured in the middle of the length 130L.
  • the material wall thickness of the section 130 is taken into account in this case, with it being assumed here, for the sake of simplicity, that the material thickness is identical for the respective different geometric designs.
  • the geometric design of the section 130, in which the form of the edges 131 can be different compared to the relatively sharp edges 131 in Fig. 1 b, is here too again firstly determined through simulation, with suitable positions for several transformer units also having been ascertained.
  • transformer units 142 and 143 are arranged on the facing-away side fully within the region of the length 130L of the section 130 and are thereby situated on outer regions, whereas a further transformer unit 144 is provided in a central region on the facing side of the section 130. It should be noted, that when calculating the deformation behaviours of the section 130 it is in particular also possible to take into account the mechanical behaviour of the one or more transformer units which are thus also encompassed in the "material characteristics" and the "material thickness or wall thickness" of the deformation section.
  • At least one transformer unit is fixed in its position, including its dimensions, such that it covers a region of maximum deformation, while other transformer units are arranged such that they are provided at least in the region of a local maximum of the deformation.
  • the transformer unit 144 can be situated at a location of a globally maximum deformation, while the transformer units 142 and 143 can be arranged at positions with locally maximum deformation.
  • the transformer units can be appropriately arranged without taking into account the global or local maximum of deformation such that, in interaction, an optimised signal is obtained for the elicited deformation in the section 130.
  • Fig. 1 d shows a further variant with adapted geometric design of the section 130, wherein transformer units 145, 147 are provided at opposite positions in the proximity of an edge region of the section 130 and similarly transformer units 146, 148 are provided at opposite positions at the opposite edge region of the region 130.
  • transformer units 145, 147 are provided at opposite positions in the proximity of an edge region of the section 130 and similarly transformer units 146, 148 are provided at opposite positions at the opposite edge region of the region 130.
  • Fig. 2a shows a schematic side view of a measuring system 280 according to a further embodiment.
  • the system 280 has a measuring element 200 and a calibration unit 290.
  • the measuring element 200 comprises a first measuring arm 210 and a second measuring arm 220, which, in the unstressed state, are separated from one another by a spacing 201 .
  • the first measuring arm 210 and the second measuring arm 220 are coupled to a deformation section 230 via corresponding connection regions 215, 225, with one or more measuring transformers, which for the sake of simplicity are not shown in Fig. 2a, being attached to the deformation section 230.
  • the corresponding measuring transformer units can be arranged as shown and described in connection with the system 180 in Figs.
  • measuring transformer units can take place on the basis of simulation calculations as is described previously for example, in other embodiments only a suitable geometry, which can be ascertained by experiments or the like or also by simulation, is sufficient and can be applied as a basis for the measuring element 200.
  • the geometric design of the deformation section 230 in particular is ascertained on the basis of simulation calculations, but in other embodiments this is not required and corresponding experimental results and other expert knowledge may be sufficient to configure the measuring element 200 for a desired area of application.
  • the measuring element 200 is in particular designed for a broadened measurement range by being able to assume different mechanical states which correspond to different measurement ranges for the forces to be measured.
  • Fig. 2b shows a schematic side view of a part of the measuring element 200, wherein a front region 21 OA of the first measuring arm and a front region 220A of the second measuring arm are shown in the unstressed state, meaning that the spacing 201 is maintained there.
  • the value 0 is however smaller than a first threshold, for example a force of several tens of Newtons, a relative deflection of the two measuring arms takes place, i.e. in particular the two front regions 21 OA, 220A, so that a new spacing 201 A is adjusted which is representative of the exerted force Fi.
  • a first threshold for example a force of several tens of Newtons
  • the relative deflection can possibly take place without appreciable elastic deformation of the two measuring arms if they possess sufficient rigidity for the force Fi which is exerting an effect. If the force Fi increases, a further reduction of the spacing 201 A takes place and the region in which the spacing 201A is not 0, i.e. as long as there is no direct mechanical contact between the two front regions 21 OA, 220A, is referred to as a first measurement range.
  • Fig. 2c shows a further mechanical state of the measuring element 200, in which a force or pair of forces F2 exerts an effect on the two measuring arms so that they come into direct contact with one another.
  • the force F2 at which a mechanical contact just occurs between the two front regions is referred to as a threshold.
  • a threshold the force F2 at which a mechanical contact just occurs between the two front regions.
  • the schematically depicted detecting unit 250 can be suitably formed here to register an electrical resistance between the front regions 21 OA, 220A, which resistance changes for example when the measuring arms overall are constructed from a material with relatively high electrical resistance.
  • an infinite resistance would be measured at an insulator or a relatively large resistance would be measured if the flow of current is taking place via the measuring arms, the transition regions and the deformation section (see Fig. 2a).
  • the resistance is decreased correspondingly through the parallel connection of the "contact resistance", such that this permits a corresponding registering of the direct contact.
  • the increase in the contact surface can contribute to a further measurable reduction of the resistance, meaning that a corresponding representative signal is obtained for the force F2.
  • the detecting device 250 can additionally or alternatively implement other measuring concepts, for instance a capacitive measurement, an inductive measurement, and the like, in order to obtain a corresponding output signal.
  • other measuring concepts for instance a capacitive measurement, an inductive measurement, and the like.
  • one or more pressure-sensitive sensors may be provided, which then output a signal which is dependent upon the force F2. It must be noted here that an appropriate mechanical stressing of such sensors is relatively low, because a stressing only occurs in a direction perpendicular to the longitudinal direction and also only when the corresponding threshold force which limits the first measurement range is exceeded. Fig.
  • FIG. 2d shows a further embodiment in which a further mechanical state is depicted in which a further rise in the force acting on the measuring arms does not lead to any further increase in the contact surface 21 1 between the front regions 21 OA and 220A, which means that, starting from a particular second threshold force, the size of an intermediate space 202 formed substantially by a rear region 21 OB of the first measuring arm and a rear region 220B of the second measuring arm is changed.
  • F3 a force which is above the second threshold
  • a suitable further detecting device 251 which outputs a signal that is a measure of the size of the intermediate space 202, 202A for example.
  • the detecting device 251 can in this case have any suitable sensors, for instance strain gauges, piezo-electrical elements, electrical components for the inductive and/or capacitive measurement and the like, which means that a further measurement range for larger forces can be provided. It is the case here too that the deformation section 230 (Fig.
  • the measuring element 200 depicted in Fig. 2d is a measuring element in which the measuring arms 210, 220 are firmly connected to one another mechanically at their front regions 210A, 210B, which means that a force exerting an effect directly onto the regions which are firmly connected to one another causes no appreciable deformation or change to the intermediate space 202.
  • the rear regions 210B, 220B react to the force to be measured, as is also already the case in the previous embodiments depicted in connection with Fig. 2d.
  • the detecting device 251 thus registers the size of the intermediate space 202, for instance by registering the deformation of the rear regions 210B, 220B and/or by registering the spacing of a specified region of the rear region 21 OB, 220B, for which purpose there are a number of suitable measuring concepts available, which have already been listed previously.
  • the inseparable front regions 21 OA, 220A give rise to a great rigidity which makes it possible to accommodate very large forces.
  • the robust mechanical structure additionally allows a very small total thickness for a given force which is to be measured.
  • the measuring arms are suitably mechanically coupled on the side (not shown) facing away from the front regions 21 OA, 220A, for instance pressed together, as schematically shown on the left side, or connected to one another by adhesive bonding, as is shown schematically on the right side of Fig. 2g, such that forces exerting an effect there have no significant effect on the size of the intermediate space 202.
  • the measuring arms 210, 220 are coupled to one another by an elastic deformation section, for instance in the form of the deformation section 230, which is formed such that a certain deformation of the section 230 is caused if the intermediate space is changed. A suitable geometric design for this can be ascertained by experimentation and in particular by simulation.
  • Transformer units can also be provided for such a suitably designed deformation section, these transformer units being able to be used in addition or alternative to the detecting device 251 , in order to ascertain the force which is to be measured.
  • the concept, implemented in the measuring system 280, of the two or more different mechanical states for implementing two or more measurement ranges can in the same way also be implemented in the measuring system 180, i.e. in the measuring element 100, in addition to the concepts described there.
  • the previously described embodiment with firmly or rigidly connected front regions 21 OA, 220A can likewise be combined with features described previously or below.
  • Figs. 3a to 3e show schematic perspective views of front regions of measuring arms which can be used in the previously described measuring elements 100, 200, for example, and also in measuring elements described below.
  • Fig. 3a shows a view of a cross-section in a perspective depiction of a first measuring arm 310 and of a second measuring arm 320, wherein surfaces 312 and 322 which are correspondingly facing one another are designed such that they are complementary to one another, i.e. such that they have a certain form fit when they lie on one another, and such that at least regions of the surface have a surface normal 322N, which make an angle with a force component FN which is to be measured.
  • the surfaces 312 and 322 have substantially smooth faces that correspondingly form an angle of more than 10 degrees and even more advantageously of 30 degrees or more, to the direction of the force component FN which is to be measured.
  • Fig. 3b shows a further variant, in which the surfaces 312 and 322 are formed as complementary curved faces, so that here too the surface normal 322N forms, in the significant regions of the curve form, a more or less large angle to the force component which is to be measured.
  • Fig. 3c shows a further variant, in which the facing and complementary surfaces 312, 322 have several curved sections, which means that, in this case too, there are many face regions with a surface normal 322N, which form an angle to the force which is to be measured.
  • Fig. 3d shows a further variant, in which the surfaces 321 , 322 are formed as wedge shapes, so that here too the surface normals 322N form an angle to the direction of the force component which is to be measured.
  • Fig. 3e shows a further variant, in which the surfaces are oriented in the direction of the deflection, such that the normal 322N points in the direction of the force which is to be measured.
  • Fig. 4a schematically shows a side view of a further measuring system 480 with a calibration unit 490 and a measuring element 400 in which a total thickness of a first measuring arm 410 and of a second measuring arm 420 is varied, or can be varied, at least in regions.
  • the characteristics of a varied or variable total thickness of a part of or of the entire measuring arms 410, 420 of the measuring element 400 can also be installed in each of the previously described measuring elements 100, 200 or also in measuring elements described below in addition to the otherwise described characteristics. In other embodiments, none or only isolated characteristics of the measuring elements 100, 200 are implemented in the measuring element 400.
  • the first measuring arm 410 and the second measuring arm 420 have a spacing 401 which can be located in a suitable range.
  • the spacing 401 in conjunction with the relevant "thickness" 410D of the first measuring arm and the "thickness" 420D of the second measuring arm gives rise to a total thickness 404 in the unstressed state.
  • the thicknesses 410D, 420D therefore correspond to dimensions of the measuring arms in a direction which also corresponds to the direction of the force component to be measured and which is oriented perpendicularly to the longitudinal direction L (Fig. 1 a).
  • the first measuring arm 410 and the second measuring arm 420 are connected by corresponding transition regions 415, 425 to a deformation section 430, which, in the event of relative deflection of the measuring arms, displays a deformation that is transformed into a signal by one or more appropriately arranged transformer units.
  • the appropriate transformer unit can be attached, at any position, to the deformation section 430 as; for example, strain gauges, piezo-electrical components, and the like.
  • the positioning of the one or more transformer units can, as explained previously, take place as explained in connection with the measuring element 100, for example.
  • the cross-sections of the measuring arms can be designed as described in connection with Figs. 3a to 3d.
  • the corresponding thicknesses 410D, 420D are possibly variable and a corresponding representative value at a given position is assumed as a measuring point for the corresponding thickness 410D, 420D.
  • the design of the measuring arm surfaces which face one another is of no significance to the total thickness 404.
  • Fig. 4b shows for example a section in which the total thickness 404 (Fig. 4a) is increased by providing an additional thickness 41 OF.
  • one or more material layers for example material foils, are applied onto the specified section of the first measuring arm.
  • the original or minimum thickness 410D is correspondingly increased by the thickness 41 OF.
  • a further thickness which is greater than the original thickness 410D but smaller than the thickness 41 OF can accordingly be installed in another section (not shown) by applying a thinner material layer or a smaller number of identical material layers.
  • 410D plus 41 OF could be installed in order to implement three different total thicknesses 404. It should be noted that a corresponding varying of the thickness can additionally or alternatively be carried out at the second measuring arm and that two regions or four or more regions of different thickness can be installed along the longitudinal extent of the measuring arms. If this is deemed to be suitable, it is also possible for more or less gradually varying thickness to be installed in one or both measuring arms by appropriately adding additional material.
  • Fig. 4c schematically shows a side view in which one or more control members 445, i.e. actuator elements, are provided, in order to controllably achieve an elongation/contraction in a certain region of the measuring element 400.
  • the one or more actuator elements 445 can be provided in the transition region 415 and/or the transition region 425 and/or in the deformation section 430, in order thus to controllably adjust the mechanical state of the measuring element 400.
  • a region of the transition region 425 is provided with one or more actuator elements 445, so that a change in the total thickness 404 is achieved when the elongation/contraction of the actuator element 445 is altered.
  • the one or more actuator elements 445 can be provided in the transition region 415 and/or the deformation section 430 in order to thereby controllably adjust the total thickness 404, for example.
  • the one or more actuator elements 445 are in this case any suitable control elements which perform a corresponding elongation/contraction, for example on the basis of an electrical signal and which must be held in a corresponding state.
  • corresponding control members are piezo-electrical elements, controllable elements based on microelectronic mechanical systems (MEMS), micromotors, suitable metals or other materials that possess, for example, a well- reproducible heat expansion, and the like.
  • a control member can also be provided in the form of a spindle driven by a revolving cylinder engine, or also manually.
  • a desired mechanical state of the one or more actuator elements 445, and thus of the measuring element 400 can thus be adjusted by applying a suitable control signal in the form of an electrical signal, a manual action, a signal that adjusts a reproducible temperature in the actuator element 445, an optical signal, and the like. This can be advantageous in order to alter the total thickness 404 within a desired range, without thereby having to alter the point of action of the force component which is to be measured.
  • a corresponding "adjustment" of the total thickness 404 can also take place dynamically during the measuring process, by the one or more actuator elements 445 being correspondingly triggered when the measuring force exerts its effect. This can lead to a changed deformation in the section 430, because the force component to be measured thus exerts an effect on a system of measuring arms, which in the unstressed state would have a changed total thickness 404. Naturally, the change of the mechanical state of the one or more actuator elements 445 can also take place prior to a direct contact of an object which is to be measured.
  • the one or more actuator elements can, in clear embodiments, be used as a sensor, by obtaining the stroke or the deflection and/or applied work of the actuator element as information and involving it for further evaluation.
  • This information can be obtained for instance by determining the number of revolutions of a revolving cylinder engine, by evaluating the control voltage of an element which reacts to voltage, and the like.
  • the triggering of the actuator element and thus the signal which is to be evaluated can for instance be altered until a given signal of the transformer unit(s) is achieved.
  • the signal of the actuator element is then an exact measure of the force which is to be measured.
  • This compensation method can also be used to calibrate the measuring element 400 without requiring further calibration components.
  • the actuator element is activated until the desired calibration value, for instance a desired zero point, is adjusted in the transformer unit. That triggering signal of the actuator element 445 which is required for this calibration value can be applied during the actual measurement or appropriately taken into account during the evaluation.
  • Fig. 5 shows a schematic sectional view of a part of measuring arms 510 and 520, which can be employed in this form in all previously described measuring elements 100, 200, 400 and also in all further described measuring elements.
  • the first measuring arm 510 and the second measuring arm 520 possess different dimensions in the longitudinal direction L, so that in this variant the second measuring arm 520, for example, has a front region 520A that fully encompasses a front region 51 OA of the first measuring arm 510 in the longitudinal direction.
  • the corresponding spacing 501 between the first measuring arm 510 and the second measuring arm 520 in the unstressed state is not formed entirely to the front, but the total thickness in the unstressed state is substantially identical over the entire extent of the measuring arms along the longitudinal direction L.
  • the important region which is to be measured can possibly be situated at a set-back location, while on the other hand the conditions must be modelled as identically as possible to the actual factors. In this manner, the force component arising at the set-back position is measured without giving rise to a falsification through the spring forces which arise in the front region, but which are present in reality and influence the overall behaviour.
  • FIG. 6 shows an embodiment in a schematic perspective depiction, with only measuring arm systems 605A, 605B, 605C, 605D being depicted, which each have a first measuring arm 610 and a second measuring arm 620.
  • the measuring arm systems 605A, 605D shown in Fig. 6 can be employed in conjunction with any of the previously described measuring elements 100, 200, 400 and measuring elements which are still to be described.
  • several measuring arm systems for example with two, three, four or more measuring arm systems, are therefore arranged in a lateral direction W perpendicular to the longitudinal direction L, so that a contact of several of the measuring arm systems 605A, 605D with a respective force component which is to be measured can take place simultaneously.
  • each of the measuring arm systems 605A, 605D is mechanically coupled to an assigned separate deformation section, wherein the corresponding deformation section may be designed as described in connection with the measuring elements 100, 200, 400.
  • the individual force components registered in the respective measuring arm systems 605A, 605D can be output to an appropriate evaluation unit as a signal and evaluated separately. If required, the individual forces to be measured may possibly be added together during the evaluation in order to thus obtain a total force. If a "mechanical" addition of two or more force components is desired, corresponding two or more measuring arm systems 605A, 605D can exert an effect on a single deformation section in order to thus ascertain the corresponding sum force.
  • Fig. 7 schematically shows a side view of a part of a measuring element, wherein a part of a connection region 725 is shown, which is coupled with a measuring arm which is not shown. Furthermore, a part of a deformation section 730 is depicted which is ultimately coupled to the measuring arm, not shown, via the connection region 725. It is also the case for the embodiment depicted in Fig. 7 that this can be combined with all measuring elements hitherto described and described below.
  • the connection region 725 in particular is suitably designed such that a high degree of response sensitivity, resolution and exactness is achieved, for example by providing appropriate cavities or material inserts 726A, 726B.
  • Fig. 8a schematically shows a side view of a measuring system 880 according to a further clear embodiment.
  • the measuring system comprises a measuring element 800 with a first measuring arm 810, a second measuring arm 820 which, in the unstressed state, form a spacing 801 therebetween, and with a deformation section 830, which is mechanically coupled to the measuring arms 810, 820 via corresponding connection regions 815, 825.
  • the same criteria apply with regard to the measuring element 800 as have already been described for the respective embodiments.
  • the measuring element 800 can be installed in the same manner as the measuring element 100 or the measuring element 200 or the measuring element 400 or can also be installed such that one or more features of one of the measuring elements in the preceding embodiments are combined in the measuring element 800.
  • the measuring elements 810, 820 are suitably formed as also described in the preceding embodiments.
  • the measuring element 800 is, with an optimised geometric design, for example on the basis of simulation calculations, suitably adapted to the respective application and/or there are several measurement ranges realised in the element 800 and/or different values are realised for the total thickness of the system made up of measuring arms 810, 820 in the element 800 and/or the measuring arms are firmly connected to one another on one side and/or the cross-sectional shapes of the measuring arms 810, 820 are designed as described previously in connection with Figs.
  • connection regions 815, 825 can be structured as described in connection with Fig. 7.
  • the system 800 further comprises a calibration unit 890 which is provided in one embodiment as a separate component and that, in addition or alternatively, is installed as a component integrated in the measuring element 800 in a further embodiment.
  • Fig. 8b shows the calibration unit 890 in a variant in which it is integrated in the element 800, for example in the form of a positioning element 813 which is provided at a precisely specified position along the longitudinal direction L at the first measuring arm 810 (as shown) and/or the second measuring arm 820.
  • the positioning element 813 is provided in any suitable form, for example in the form of a relief or depression, in order to thus receive a support of a positioning weight 891 which is thus exactly positioned in the longitudinal direction L.
  • the measuring element 800 for example is oriented such that its measuring arms 810, 820 are arranged horizontally, as a result of which, when the calibration mass 891 is applied, a force component acting perpendicularly to the longitudinal direction L occurs at a precisely specified position, i.e. the position of the positioning element 813, so that it is possible to calibrate the response behaviour of the deformation section 830 (Fig. 8a) through the known size of the calibration force 891.
  • a calibration length element which is not shown, is applied in order to cause a precisely defined deflection which is then used to calibrate the deformation section 830. Both variants can also be employed together.
  • Fig. 8c schematically shows a side view of a further embodiment of the calibration unit 890, which is provided as a separate component.
  • the calibration unit 890 has a cap shape or a cup shape in which there is formed a recess 892 such that the first and second measuring arms 810, 820 can be introduced in a precisely defined manner.
  • the recess 892 possesses a suitable width, i.e. a dimension in the direction perpendicular to the plane of projection of Fig. 8c, and a suitable thickness, i.e.
  • the calibration unit 890 has an aperture 893 which is positioned precisely along the longitudinal direction L so that a calibration force 891 , for instance in the form of a weight, can exert an effect on the measuring arm through the aperture 893 via an appropriate pressure rod 891 A.
  • a calibration force 891 for instance in the form of a weight
  • a suitable support or a housing is provided for the measuring element, so that a mechanically robust arrangement is obtained.
  • a housing is not shown.
  • appropriate electronic, optoelectronic, micromechanically electronic components and the like which can serve to acquire signals, evaluate signals or prepare signals, can be accommodated partially or fully at a suitable location in the measuring element itself and/or in an appropriate housing at a suitable location.
  • suitable semiconductor chips or other suitable substrates with optical, electronic, mechanical components, which are assembled thereon can be accommodated at a suitable location and also the respective supply lines are suitably provided in the form of wires, conductive paths, and the like at suitable locations in the measuring element and/or the housing.
  • significant steps of a corresponding evaluation of signals can be performed in the measuring element or in an associated housing itself, and an appropriately prepared signal can be transmitted to a further electronic evaluation system, for instance a computer, and the like.
  • a further electronic evaluation system for instance a computer, and the like.
  • only substantially unprocessed signals are transmitted to the electronic evaluation system.
  • a transmission of signals can take place for example through wired connections or also through wireless communication channels such that a high degree of flexibility is achieved in particular when a measuring system is applied with the measuring element according to the invention.
  • transformer units 140, 141, 142, 143, 144, 145, transformer units

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
  • Force Measurement Appropriate To Specific Purposes (AREA)
PCT/EP2017/084791 2016-12-29 2017-12-29 Measuring element, measuring system, and method of providing a measuring element for measuring forces WO2018122365A1 (en)

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CN110121636B (zh) 2021-06-29
DE102016226282B4 (de) 2018-09-20
EP3563131A1 (en) 2019-11-06
CN110121636A (zh) 2019-08-13
US11346733B2 (en) 2022-05-31
US20190316977A1 (en) 2019-10-17

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